From patent literature and from other technical publications it is known to utilize photoluminescence or absorption characteristics in semiconductor materials for measurement of parameters, such as temperature and pressure.
It has been proposed to use the shift of the absorption edge of bulk GaAs for pressure sensing. However this can result in severe difficulties, such as thermal stabilization and temperature cross-talk effects. After compensation the remaining temperature error, for example, can be 1.5 bar/K, whereas without compensation it could be 40 bar/K.
Others have demonstrated that the luminescence spectra and absorption of e.g. GaAs/Al(x)Ga(1-x)As, InGaAs/GaAs systems can be useful for pressure calibration. It has been purported to use the shift of laser lines of AlGaAs and InGaAs/GaAs quantum-well laser structures, such as for the high pressure regime (several GPa). For the latter, problems can be related to mode hopping and hysteresis. Apart from using the band gap shift for optical pressure sensing it can also be used for tuning the laser wavelength of semiconductor laser diodes. Tuning ranges larger than 200 nm have, for example, been reported